How We Ran Our Tests

We have implemented automatic profiling features into the latest 7.1 beta version of PRTG which measure the execution times of various AJAX and Javascript functions. We ran our tests on a DELL Precision 390 with Intel Core 2 X6800 CPU with 4 GB RAM under Windows 7 64-bit.
The browsers we tested are:

Google Chrome 1.0.154.48 (Stable)

Google Chrome 2.0.164 Beta (Developer Preview)

Mozilla Firefox 3.0.6

Mozilla Firefox 3.1 beta 2

Opera 9.63

Apple Safari 4 beta 528.16

Microsoft Internet Explorer 7: IE7.0.6001 (tests were run on Windows Vista, same Hardware)

Results 1: DOM Manipulation Performance

Our first set of tests measures the execution times of various Javascript functions that manipulate the page's DOM (Document Object Model) inside the browser. The results are:
The fastest browser is Safari 2 Beta with Chrome as a close second. Firefox 3.1 Beta 2 is better than FF 3.0.6, but still 60% slower than the fastest. Both Internet Explorer versions are way too slow, with IE7 taking 7 times as long as Chrome to perform our complete test parcour. On IE7 some tests took 35 times longer than on Chrome.

Results 2: AJAX Performance

The second set of tests performs a number of HTTP calls to the PRTG webserver and inserts the results into the page (e.g. loading a tab, refreshing data).
In this case Firefox 3.1 Beta, Safari and Chrome are more or less equal in performance. The Firefox upgrade from V3.0 to V3.1 boosts performance considerably. Both IEs are very slow, up to 8 times slower than Chrome.

Conclusion

Currently our clear browser-of-choice for PRTG is Chrome. It is as fast as Safari 4 and runs PRTG more reliably (we have seen installations of Safari that did not show PRTG's context menus from time to time). Firefox 3.1 is the second best choice. IE7 and IE8 are way too slow.